X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 02 Mar 2010 13:07:03 -0500 Message-ID: X-Original-Return-Path: Received: from imr-da02.mx.aol.com ([205.188.105.144] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTP id 4143368 for lml@lancaironline.net; Tue, 02 Mar 2010 11:47:26 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.144; envelope-from=Sky2high@aol.com Received: from imo-ma02.mx.aol.com (imo-ma02.mx.aol.com [64.12.78.137]) by imr-da02.mx.aol.com (8.14.1/8.14.1) with ESMTP id o22Gke5L007474 for ; Tue, 2 Mar 2010 11:46:40 -0500 Received: from Sky2high@aol.com by imo-ma02.mx.aol.com (mail_out_v42.9.) id q.cff.6bc2f31e (34911) for ; Tue, 2 Mar 2010 11:46:35 -0500 (EST) Received: from magic-m18.mail.aol.com (magic-m18.mail.aol.com [172.21.136.206]) by cia-da02.mx.aol.com (v127_r1.2) with ESMTP id MAILCIADA028-885f4b8d40ebb2; Tue, 02 Mar 2010 11:46:35 -0500 From: Sky2high@aol.com X-Original-Message-ID: <5ddf0.366b178d.38be9aea@aol.com> X-Original-Date: Tue, 2 Mar 2010 11:46:34 EST Subject: Re: [LML] Re: Reichel Trim Wheel X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_5ddf0.366b178d.38be9aea_boundary" X-Mailer: AOL 9.5 sub 155 X-AOL-ORIG-IP: 67.175.242.202 X-AOL-IP: 172.21.136.206 X-Spam-Flag:NO X-AOL-SENDER: Sky2high@aol.com --part1_5ddf0.366b178d.38be9aea_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit With reference to Marv's explanation: There is more to it than benefits from reduced weight and drag. Many, if not most, LNC2 builder/pilots reduced the arm of the elevator bell crank from 4 inches to 3. This modification resulted in reducing the stick throw by 25% and also increasing stick forces by 25% - a really good result because of the pitch "sensitivity" of these aircraft. Of course when one changes a part of a system, the whole system is affected. Finer pilot control of stick movement was required (famous two-finger grip) and a stronger trim spring was needed to manage the higher trim forces. A consequence of using the stiffer spring was the need for more friction to hold the crucifix trim lever position and more difficulty in fine tuning pitch trim. The Reichel trim wheel resolves the spring/friction issues while still allowing the pilot to overcome any trim setting with stick movement (that is, causing the trim wheel to unwind). Benefits abound from this system including no possible electric trim runaway in the all important pitch axis. Another benefit of the Reichel Wheel is the window with its precise trim position indicator. Mine is marked with the neutral elevator position and the elevator is set to that position before each takeoff - a known control surface position with pitch control totally in my hands. Since my experience is with my own small tail 320 (and others with small tails), we will have to await the comments of others on its efficacy with either a Mk II tail 300 series Lancair or a Legacy. Scott Krueger In a message dated 3/2/2010 10:12:48 A.M. Central Standard Time, marv@lancair.net writes: Posted for "Bay Elliott" : Hi Marv, I am a relatively new Legacy builder (last 6 months) and I am not familiar with the Reichel Trim Wheel. What are the advantages of this system over others and is it applicable to the Legacy? Warm Regards, Bay Elliott Executive Vice President, The Farwell Group, Inc. Executive Recruiting Consultants (305) 529 4811 bay@farwellgroup.com [I thought I would move this out onto the LML to invite further discussion and get some assistance from folks who know more about the intricacies of trim systems than I do. The earlier LNC2 was designed with a trim system that used a spring bias applied to the elevator pushrod to control the overall elevator position. It was controlled by a small cruciform trim lever that moved the biasing springs forward and aft. Dick Reichel invented his trim wheel to replace the lever, allow finer and more precise trim adjustments, and to provide folks with the same sort of trim wheel that they had flown with in any number of certified aircraft. Trimming the location of the entire control surface is probably aerodynamically preferable (less drag) to moving a trim tab to use the airflow to move the control surface, and the removal of the trim tab eliminates its weight and complexity, as well as those of the servo motor and linkages... ie, less counterweight required for balance. There are probably other aero issues, but I leave those things to folks more knowledgable than I in these matters. Whether or not a a spring biased trim system would be applicable to the Legacy, I can't see why not, at least for those folks who are still building and can opt to incorporate it into their control system... I don't know how the trim tab is built on the Legacy elevator, but if it's cut from the elevator similarly to the method used on the LNC2, that part of the process could be bypassed and the work, weight and complexity of the trim tab mechanism could all be left out. To my knowledge no one has incorporated this into a Legacy, but that doesn't mean that it couldn't be done. The only disadvantage with the spring bias system at this point is that it is totally manual. Once I finish with the basic trim wheel system I'm going to look into motorizing it while still allowing manual adjustments. ] -- For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html --part1_5ddf0.366b178d.38be9aea_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
With reference to Marv's explanation:
 
There is more to it than benefits from reduced weight and drag. = Many,=20 if not most, LNC2 builder/pilots reduced the arm of the elevator bell cran= k from=20 4 inches to 3.  This modification resulted in reducing the stick thro= w by=20 25% and also increasing stick forces by 25% - a really good result because= of=20 the pitch "sensitivity" of these aircraft.  Of course when one= changes=20 a part of a system, the whole system is affected.  Finer pilot contro= l of=20 stick movement was required (famous two-finger grip) and a stronger= trim=20 spring was needed to manage the higher trim forces.  A consequence of= using=20 the stiffer spring was the need for more friction to hold the cr= ucifix=20 trim lever position and more difficulty in fine tuning pitch trim.&nb= sp;=20 The Reichel trim wheel resolves the spring/friction issues while still all= owing=20 the pilot to overcome any trim setting with stick movement (that is, causi= ng the=20 trim wheel to unwind).  Benefits abound from this system including no= =20 possible electric trim runaway in the all important pitch axis.
 
Another benefit of the Reichel Wheel is the window with its= =20 precise trim position indicator.  Mine is marked with the neutra= l=20 elevator position and the elevator is set to that position before each tak= eoff -=20 a known control surface position with pitch control totally in my=20 hands.
 
Since my experience is with my own small tail 320 (and others with sm= all=20 tails), we will have to await the comments of others on its efficacy with= either=20 a Mk II tail 300 series Lancair or a Legacy.   
 
Scott Krueger
 
In a message dated 3/2/2010 10:12:48 A.M. Central Standard Time,=20 marv@lancair.net writes:
Posted for "Bay Elliott"=20 <bay@farwellgroup.com>:

 Hi Marv,
 I am a rela= tively=20 new Legacy builder (last 6 months) and I am not familiar
with the Re= ichel=20 Trim Wheel.  What are the advantages of this system over
o= thers=20 and is it applicable to the Legacy?

 Warm=20 Regards,

 Bay Elliott
 Executive Vice President, The= =20 Farwell Group, Inc.  
 Executive Recruiting=20 Consultants
 (305) 529=20 4811      bay@farwellgroup.com
 

[I=20 thought I would move this out onto the LML to invite further discussion= and=20 get some assistance from folks who know more about the intricacies of tr= im=20 systems than I do. 

The earlier LNC2 was designed with a tr= im=20 system that used a spring bias applied to the elevator pushrod to contro= l the=20 overall elevator position.  It was controlled by a small cruciform= trim=20 lever that moved the biasing springs forward and aft.  Dick Reichel= =20 invented his trim wheel to replace the lever, allow finer and more preci= se=20 trim adjustments, and to provide folks with the same sort of trim wheel= that=20 they had flown with in any number of certified aircraft. =20

Trimming the location of the entire control surface is probably= =20 aerodynamically preferable (less drag) to moving a trim tab to use the= airflow=20 to move the control surface, and the removal of the trim tab eliminates= its=20 weight and complexity, as well as those of the servo motor and linkages.= .. ie,=20 less counterweight required for balance.  There are probably other= aero=20 issues, but I leave those things to folks more knowledgable than I in th= ese=20 matters. 

Whether or not a a spring biased trim system woul= d be=20 applicable to the Legacy, I can't see why not, at least for those folks= who=20 are still building and can opt to incorporate it into their control syst= em...=20 I don't know how the trim tab is built on the Legacy elevator, but if it= 's cut=20 from the elevator similarly to the method used on the LNC2, that part of= the=20 process could be bypassed and the work, weight and complexity of the tri= m tab=20 mechanism could all be left out.  To my knowledge no one has incorp= orated=20 this into a Legacy, but that doesn't mean that it couldn't be done. = ;=20

The only disadvantage with the spring bias system at this point= is=20 that it is totally manual.  Once I finish with the basic trim wheel= =20 system I'm going to look into motorizing it while still allowing manual= =20 adjustments.

 <Marv>     &nbs= p;  =20 ]



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